Crude chitin synthetase preparations from the mycelial and yeast forms of MUCOP rouxii behaved differently. The mycelial preparations, incubated at 28 “C, lost virtually all chitin synthetase activity in a few hours; by contrast, the activity of enzyme preparations from yeast cells increased several fold during similar incubations. These spontaneous changes were probably caused by endogenous pr...

In prior studies, we demonstrated that glucuronoxylomannan (GXM), the major capsular polysaccharide of the fungal pathogen Cryptococcus neoformans, interacts with chitin oligomers at the cell wall-capsule interface. The structural determinants regulating these carbohydrate-carbohydrate interactions, as well as the functions of these structures, have remained unknown. In this study, we demonstra...

To ascertain the directionality of chitin synthesis by yeast plasma membranes, the external surface of Saccharomyces cerevisiae protoplasts was labeled with ferritin--concanavalin A. After protoplast lysis, plasma membranes were isolated and treated with trypsin to activate chitin synthase (UDP-2-acetamido-2-deoxy-D-glucose:chitin 4-beta-acetamidodeoxy-D-glucosyl-transferase, EC 2.4.1.16). The ...

Chitin synthetase was isolated and purified 120-fold from the supernatant fraction (54,500 x g) of broken yeast cells of Mucor rouxii. The purified preparations consisted mainly of chitin synthetase particles (chitosomes) with an average size larger than 7 x 10” daltons (by gel filtration) and an average sedimentation coefficient of 105 S. The samples also contained other enzyme complexes (fatt...

Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hyd...

Chitin is an abundant renewable polysaccharide, next only to cellulose. Chitinases are important for effective utilization of this biopolymer. Chitinase D from Serratia proteamaculans (SpChiD) is a single domain chitinase with both hydrolytic and transglycosylation (TG) activities. SpChiD had less of hydrolytic activity on insoluble polymeric chitin substrates due to the absence of auxiliary bi...

Totally tubular chitin lies create uniform tracheal tubes by molding them around an expanding chitin filament, according to Anna Tonning, Anne Uv, and colleagues (Göteborg University, Göteborg, Sweden). Uv’s group suspected that chitin may be involved in shaping tracheal tubes after observing that a chitin synthase mutant forms tracheal branches that look like sausages rather than uniform cylin...

A new method for quick chitin isolation from the shells of crab, crayfish and shrimp is described. The main difference between the new method and the conventional method is two sodium hypochlorite (NaClO) treatments for 10 min each before the processes of demineralisation and deproteinisation. After the NaClO treatment, only 15 min is adequate for the demineralisation and 20 min for the deprote...

A thermostable Chitinase Chi1 from Myceliophthora thermophila C1 was homologously produced and characterized. Chitinase Chi1 shows high thermostability at 40 °C (>140 h 90% activity), 50 °C (>168 h 90% activity), and 55 °C (half-life 48 h). Chitinase Chi1 has broad substrate specificity and converts chitin, chitosan, modified chitosan, and chitin oligosaccharides. The activity of Chitinase Chi1...

Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of ...